A Collection on Spectroscopy.

[G. D. Liveing and Sir I. Dewar. Collected papers on Spectroscopy. Cambridge—1915 (556 pp.).]

In the present volume are collected the studies of the eminent English spectroscopists, carried out by them over the course of almost 40 years and published in Philosoph. Magazine, Proceed. of the Royal Society, Proceed. of the Cambridge Philosoph. Society, Proceed. of the Royal Institution, Philosoph. Transactions of the Royal Society.

For persons engaged in spectroscopy, the publication of Liveing’s and Dewar’s works is of very great importance. The appearance of the edition leaves nothing better to be desired.

P. Lazarev.

Abraham. Theory of Electricity.

(M. Abraham. Theorie der Elektrizität. Zweiter Band. Elektromagnetische Theorie der Strahlung. Dritte Auflage. 1914. (Teubner).)

The third edition of the second volume of Abraham’s classical course has been greatly expanded and altered in comparison with the second. Some of these changes had already been predetermined by the revision to which the fourth edition of the first volume, issued in 1912, was subjected. Thus, for example, the theory of telegraphy without wires was transferred to the first volume and now, naturally, is absent from the second volume; the reworking of this chapter in the first volume also pointed to changes in the chapter on the electrodynamics of moving bodies. But in addition to such and other minor changes and additions, natural for any new edition (new experimental data, references to the most recent literature, etc.), in the third edition we find a large number of far more important changes and additions. These changes were brought about by the rapid development of the electrodynamics of moving bodies in recent years, in which, alongside Einstein, Minkowski, and other outstanding physicists, the author himself took a large part, as well as by the new major successes of electron theory. They found expression in a whole series of new paragraphs included in the book, and in the sometimes radical reworking of other paragraphs and even chapters. In view of the extraordinary importance of the questions that have undergone new treatment and consideration—such as, for example, the magneton theory and the generalized principle of relativity—it seems, of course, desirable to indicate briefly the principal changes. The most important of them are the following.

In the chapter on the dynamics of electrons, § 23 deserves special attention, in which the doctrine of the impulse of the energy flux and of its inertia is set forth; the author substantiates it independently of the principle of relativity.